Read your test strips and diagnose water problems instantly. Supports AquaChek, HTH, Taylor, Leisure Time, and Clorox strips.
Click the color that matches each pad on your test strip.
Select the issue you're experiencing with your hot tub water.
HTReminder uses AI to read your test strip in seconds. Just snap a photo and get instant, accurate recommendations.
Our analyzer supports the most popular hot tub and spa test strip brands. Each brand uses slightly different color charts, so selecting your brand ensures accurate readings.
| Brand | Tests Included | Best For |
|---|---|---|
| AquaChek | pH, Free Chlorine, Bromine, Alkalinity, Hardness | Most accurate color matching, widely available |
| HTH | pH, Free Chlorine, Bromine, Alkalinity, Hardness | Great value, available at most pool stores |
| Taylor | pH, Free Chlorine, Bromine, Alkalinity, Hardness | Professional-grade accuracy |
| Leisure Time | pH, Free Chlorine, Bromine, Alkalinity, Hardness | Designed specifically for spas and hot tubs |
| Clorox | pH, Free Chlorine, Bromine, Alkalinity, Hardness | Budget-friendly, easy to find |
Don't see your brand? The color scales are similar across most brands. Try AquaChek as a default - it works well for most generic strips too.
Test strips are the quickest way to check your hot tub's water chemistry. Here's how to get accurate readings every time:
Keeping your water balanced prevents equipment damage, skin irritation, and keeps your spa safe and comfortable.
| Parameter | Ideal Range | Why It Matters |
|---|---|---|
| pH Level | 7.2 - 7.8 | Controls acidity. Too low causes corrosion; too high reduces sanitizer effectiveness. |
| Free Chlorine | 1 - 3 ppm | Kills bacteria and contaminants. Too low allows growth; too high causes irritation. |
| Bromine | 3 - 5 ppm | Alternative sanitizer. More stable than chlorine at high temperatures. |
| Total Alkalinity | 80 - 120 ppm | Buffers pH. Low alkalinity causes pH swings; high causes cloudy water. |
| Calcium Hardness | 150 - 250 ppm | Prevents corrosion and scale. Too low damages equipment; too high causes buildup. |
Most water problems have simple fixes. Here's what causes common issues and how to resolve them:
Causes: High pH, low sanitizer, dirty filter, high total dissolved solids, or body oils and lotions.
Fix: Test and balance pH (7.2-7.8), shock the water, clean or replace filter, and ensure adequate sanitizer levels.
Causes: Soap residue, lotions, detergent from swimsuits, or low calcium hardness.
Fix: Add foam reducer for quick relief. Long-term: shower before use, wash suits without detergent, increase calcium if low.
Causes: Low sanitizer levels allowing algae growth, or copper from corroding equipment.
Fix: Shock heavily (3-4x normal dose), brush surfaces, run filter 24/7, and maintain higher sanitizer for a few days.
Causes: Chloramines (combined chlorine) from inadequate sanitation, not too much chlorine.
Fix: Shock the water to break apart chloramines. This eliminates the smell by converting them to gas.
Causes: pH too high or too low, chloramines, or excessive sanitizer levels.
Fix: Balance pH to 7.2-7.8, shock to remove chloramines, wait for sanitizer levels to drop if too high.
Causes: High calcium hardness, high pH, or high alkalinity causing calcium to precipitate.
Fix: Lower pH and alkalinity, use a scale preventer, and consider partial drain if calcium is very high.
Test your water 2-3 times per week for optimal maintenance. If you use your hot tub daily, test before each use. Always test after adding chemicals, heavy use, or refilling.
Both are effective sanitizers. Chlorine is cheaper and works faster, but breaks down quickly in hot water. Bromine is more stable at high temperatures and gentler on skin, making it popular for hot tubs despite costing more.
Low total alkalinity causes pH to swing easily. Alkalinity acts as a buffer - if it's below 80 ppm, raise it first using alkalinity increaser. Once alkalinity is stable, pH will be much easier to control.
Drain every 3-4 months, or when total dissolved solids (TDS) get too high. Signs it's time: water looks dull even when balanced, foam won't go away, or chemical demand keeps increasing.
Yes, but spa-specific strips are better. Pool strips may not test for bromine, and the ranges shown may be optimized for pools (which run cooler). Spa strips account for the higher temperatures and different chemistry needs of hot tubs.
